2012 5.0L Throttle Response?

[SixFootSix]

Can someone with a 2012 5.0L please tell me is this is normal throttle response for a 2012 5.0 non RSpec.

With the engine warmed up and gear selection in park, punch and release the accelerator and see if the RPMs rise to 4,000 and stay there for 1-2 seconds before dropping back to 600 RPM.

It seems very unusual to me that the engine holds the RPM at the high point after your foot is not on the accelerator.

Thank you

 

[landtuna]

Can someone with a 2012 5.0L please tell me is this is normal throttle response for a 2012 5.0 non RSpec.

With the engine warmed up and gear selection in park, punch and release the accelerator and see if the RPMs rise to 4,000 and stay there for 1-2 seconds before dropping back to 600 RPM.

It seems very unusual to me that the engine holds the RPM at the high point after your foot is not on the accelerator.

Thank you

Tested it last night and no, I would say your response is not normal. My RPM's climbed to about 4K and immediately dropped back to idle when the throttle was released. The revs didn't drop like a rock but they did drop quickly. I am opining the slightly slower drop has something to do with the emissions controls as in the old days dropping to idle that quickly would shoot out a plug of unburned fuel.

In the interest of full disclosure, I am completely stock but with the spacer installed on the lip of the air cleaner intake flap. Not sure whether that might make a difference or not but don't think so.

 

[LandoAWD]

Rev hang on DBW cars is not uncommon, but as I've modified my flapper, testing would not be apples-apples..

 

[NSXNEXT]

Completely natural and no there is no way to resolve it sans custom ECU programming which is still not available on the 5.0 ECU.

Here's some light reading on the topic.
http://www.revhang.altervista.org

 

[dmitriylm]

Rev hang is tied to emissions if I recall correctly. It's present in just about all cars these days.

 

[AgentSmith007]

My 2009 VW Routan (made by Chrysler) minivan does that, takes 1-2 seconds to drop to 600-700 RPM from 4000.